2003 WR450 has starting/charging issue

[RockRogue]

Hey guys,

I just recently bought a 2003 WR450. I LOVE ridign this bike! On my first ride, the bike ran great, and the E start and kick start both worked very well. After riding for about 2 hours, the red light by the ignition button turned off. I thought it burned out, the bike still started after that (I don't remember if I used the button or kick).

After the ride, I went int he garage and noticed the headlight was on. Oops, dead battery. The starter solenoid just clicked at me when I tried to start it.

Second ride: it kicked right up and rode fine, but the battery never charged. Starter button didn't even get the solenoid to click at me.

I pulled the seat, and ran the bike, and the battery fluctuated between 9 and 11 volts. After that, I put a 12v battery charger on it for 6 hours, and it read 13v when I was done. E-start still not doing anything. I pulled the radiator side plastic and checked the resistance between the yellow and white wire (A/C Magneto coil). It is .4 Ohms, which is within the facory range (it is something like .28 to .44 ohms).

Where do I go from here? I am thinking recharge the battery, and check the voltage with the starter button pressed? Make sure it is above 11 volts? I am pretty sure my battery is TOAST, but it seems I am also having a charging circuit issue not related to the A/C magneto. I really don't want to replace my battery with a new one and proceed to kill the new battery. The FSM doesn't describe a test for the regulator, but that is the only other thing I can thing of that could be wrong. I checked my plugs, and they all look good to me.

And just because every thread deserves a photo....

[William1]

If... the battery volatage read 13 and the solenoid clicked, I bet the battery has had it. What is the voltage when you hit the button? S/B at least 12.5

If the battery is bad, you will not get an accurate voltage output from the charging system. Whe you charge a battery and check the voltage as soon as you pull it off the charger, you will not get an accurate value, you must wait at least 30 minutes, even then, a no load value is only a start of the testing.

[redswr]

yeah i just had to replace my battery cause of that... now i keep it on a battery tender when i'm not riding

[miweber929]

Hey guys,

I just recently bought a 2003 WR450. I LOVE ridign this bike! On my first ride, the bike ran great, and the E start and kick start both worked very well. After riding for about 2 hours, the red light by the ignition button turned off. I thought it burned out, the bike still started after that (I don't remember if I used the button or kick).

After the ride, I went int he garage and noticed the headlight was on. Oops, dead battery. The starter solenoid just clicked at me when I tried to start it.

Second ride: it kicked right up and rode fine, but the battery never charged. Starter button didn't even get the solenoid to click at me.

I pulled the seat, and ran the bike, and the battery fluctuated between 9 and 11 volts. After that, I put a 12v battery charger on it for 6 hours, and it read 13v when I was done. E-start still not doing anything. I pulled the radiator side plastic and checked the resistance between the yellow and white wire (A/C Magneto coil). It is .4 Ohms, which is within the facory range (it is something like .28 to .44 ohms).

Where do I go from here? I am thinking recharge the battery, and check the voltage with the starter button pressed? Make sure it is above 11 volts? I am pretty sure my battery is TOAST, but it seems I am also having a charging circuit issue not related to the A/C magneto. I really don't want to replace my battery with a new one and proceed to kill the new battery. The FSM doesn't describe a test for the regulator, but that is the only other thing I can thing of that could be wrong. I checked my plugs, and they all look good to me.

And just because every thread deserves a photo....

Couple things to note here as you are troubleshooting are on my 04 (essentially the exact same bike) the red ignition led goes out as soon as the engine starts which I believe is normal. Secondly, on my bike which is a completely stock charging system, the headlight will only turn on with the engine running. Both of these are normal as I understand it on a stock WR450.

Sounds like you have a BD kit or at least a modified stator if your headlight can be left on without the engine running. Not that it affects how you troubleshoot the system, but in case you weren't aware your electrical system is not stock and you may see different readings than the manual may state.

I agree with William, sounds like a bad battery under load. If it's dragging down the charging system, the only way properly to test is with a known good battery. Buy a new one, charge it and test the system. You shouldnt hurt it unless you ride it a while without testing.

Mike

[RockRogue]

Separate note... maybe. What is this thing for? It goes into the wiring harness on the frame by the fuel tank. Was never connected when I bought the bike, and I just found it.

[redswr]

Separate note... maybe. What is this thing for? It goes into the wiring harness on the frame by the fuel tank. Was never connected when I bought the bike, and I just found it.

that looks to me like the nuetral saftey cable... i just replaced mine cause it broke. there should be a spot on the clutch for it to fit into...

[RockRogue]

that looks to me like the nuetral saftey cable... i just replaced mine cause it broke. there should be a spot on the clutch for it to fit into...

THat would explain why I have to have my bike in nuetral to restart it on the trail... ?

[redswr]

THat would explain why I have to have my bike in nuetral to restart it on the trail... ?:lol:

yeah it makes it to where it'll only do it in gear if the clutch is pulled...

[RockRogue]

Well there isn't a place nearby with a battery that is reasonably priced. I will have to order one online and wait for it to show up before I can get this thing tested on a good battery.

[RockRogue]

I did a final battery test. Overnight charge on an old automatic charger I have.

Voltage on battery after sitting for 3 days hooked up to bike with no load = 13V.

The following readings were all taken in about 2 minutes:

Ignition on = 12.5V

Start button depressed (solenoid click only, tried 4 times) = 5-7V

Ignition off = 12.6V

Ignition on = 10.4V

I think this is conclusive. My battery is worthless now. I will order a new one tomorrow.

[RockRogue]

I was lazy for a while and didn't swap my battery. Here is how it went:

I got my $45 battery from amazon, and it had 13V out of the box. I put it on an auto 2 amp charger overnight (which stayed on trickle the whole time).

I waited a few weeks with the battery not on the ground before I found time to work on it, still had 12.9V+. I installed the battery, kickstarted the bike, and the voltage is at 14V at idle, and 14.3V when I give it some gas (I don't know the RPM, maybe 5K?).

So, problem solved. This result confirms that charging system diagnosis on a confirmed dead (permanently) battery is of questionable usefullness.

?